1. Field of the Invention
The invention concerns devices and apparatus for the separation of blood serum and blood plasma, with the aid of centrifugal force, from whole blood mixtures.
2. Brief Description of the Prior Art
Devices and apparatus for the separation of blood serum and blood plasma from clotted whole blood and anticoagulant treated whole blood, respectively, by the aid of centrifugal force have been known prior to my invention. Representative of such devices are those disclosed in U.S. Pat. No. 3,508,653.
In general, the devices of the prior art employ a solid, elastomeric plug or piston which may or may not have a filter element mounted therein. The elastomeric piston forms a sliding seal with the inner walls of a tubular container for the blood mixture to be separated. The disadvantage of prior art devices employing solid elastomeric plugs as pistons resides in the fact that they must meet dimensional specifications of a very narrow range in order that a proper and effective seal is obtained between the collection container wall and the piston member.
The devices and assemblies of my invention are relatively simple in construction, and do not require the precise dimensional specifications of solid piston members previously employed for the separation of blood plasma or blood serum.